Study Identifies Face Coverings That Are Most And Least Effective – ClickLancashire

The quest began when a professor at Duke’s School of Medicine was assisting a local group buy masks in bulk to distribute to community members in need.
In the study, the scientists evaluated the effectiveness of 14 different types of masks and other frequently substituted face coverings, using a simple approach in which either one male speaker or, in some cases, four speakers wore each mask while standing in a dark enclosure. “The laser beam is expanded vertically to form a thin sheet of light,…

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